1. Field of the Invention
The present invention is directed to x-ray scanning devices of the type wherein an article to be examined is moved between an x-ray source and a radiation detector, and in particular to the types of x-ray scanners suitable for examining baggage at airports.
2. Description of the Prior Art
X-ray scanners are known in the art which include an xray source having a diaphragm for generating a fan-shape x-ray beam. An article to be examined is moved, such as on a conveyor, through the fan-shaped x-ray beam. A series of radiation detectors are disposed on an opposite side of the article from the x-ray source. The detector is disposed such that the two marginal rays of the x-ray beam, which essentially completely permeates the examination space, are incident at the extreme edges of the detector. The signals obtained from the detector are processed, and an image constructed therefrom is displayed on a monitor.
X-ray scanners of this type are utilized for detecting weapons, particularly at airports. The images produces with such conventional devices show low-absorption articles indistinctly, due to the high voltage of, for example, about 140 kV required for metal penetration. Such articles, such as plastic explosives, can therefore be overlooked in luggage packed in a mixed fashion.